After a month of on-and-off work, I made some major breakthroughs. I started from scratch with a new Micropython project and manually configured DMA by hand via registers. Here's a capture from it (using an 80Khz sample rate!): https://i.imgur.com/KbvqN7f.png And the corresponding trace from my anal...

OK, I haven't solved the low-voltage noise problem, but I did make headway obtaining direct-register control of the ADC. Turns out you need to de-assert the peripheral's RESET line (and probably enable it's clock) via the undocumented bit #28 of these two registers: SYSTEM_PERIP_RST_EN0_REG and SYST...

I also tested some one-shot code under MicroPython and am getting clean results. I'm not clear why the continuous mode samples have the artifact. I've been trying to set up the ADC registers by hand in MicroPython, using mem32(), but have found my writes to registers like APB_SARADC_CTRL_REG and APB...

I'm using ADC1 on the ESP32-S3 in Continuous mode, 10kHZ sample rate, 11dB attenuation, and I'm getting some weird noise or "ringing" in the troughs of the trace below: https://i.imgur.com/fb44CQP.png Here's an analog logic probe capture of the exact same signal (measured near the IO pin): https://i...